The foundations were laid by a two-try, first-half salvo but St Mary's were within touching distance of their first victory in four rounds after Marcus O'Driscoll's classy sidestepping try and 14 points from the boot of Conor Dean.

Trinity's defence out wide was found wanting as the Light Blues climbed into second place - 10 points behind unbeaten leaders Lansdowne. The students picked up a bonus point thanks to a brace from Michael Silvester.

There was delight for bottom side Buccaneers as they ended their seven-match losing streak with a 19-13 defeat of UCD at Dubarry Park.

Buccs captain Shane Layden chipped in with a try and winger Rory O'Connor also touched down for the seventh time this season, while Luke Carty kicked nine points off the tee.

A brace of tries from former captain Ger Slattery was not enough for Young Munster as Clontarf's young replacement Conor Kelly landed a last-gasp, match-winning penalty in a thrilling 23-22 victory at Tom Clifford Park.

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The sides split six tries, with backs Rob McGrath, Jack Power and Sean O'Brien touching down for 'Tarf.

Meanwhile, Old Belvedere jumped two places up to third in Division 1B after overcoming Naas 28-10 at Anglesea Road.

Banbridge started and finished the scoring at Donnybrook with tries from Conor Field and Caleb Montgomery, but Old Wesley edged their way to a 21-20 win with Jack Maybury kicking 11 points and Cronan Gleeson and James O'Donovan contributing tries.

Centre Harry Fleming scored the only try of the Munster derby between Dolphin and UL Bohemians, helping the Limerick men end their four-match losing run with a 13-6 success.

The day's other game in Cork finished in a 22-18 win for a Johnny McPhillips-inspired Ballynahinch at UCC.

Shannon extended their lead at the summit to four points thanks to a four-try 27-15 dismissal of Ballymena at Thomond Park.

Former Ireland U-20 international Kelvin Brown bagged a try, while Conor Fitzgerald's 12 points took his season's haul to 93.